I used a compresser. and a parts picture to guide me. It's not as bad as you think. Three screws and three pins and the while thing comes appart, it's great.
It's a combo of the 48 and the 46. It's the underlever of the 46 with the breech and piston mechanisim of the 48.... kinda combime these two pics below. The only PITA part of it to remove the pivot point from the breech, this is the thing that the cocking arm fastens to. it is held in by a tiny screw that goes in for the front of the breech. once it's removed the pivot point comes out, allowing you to slide the breech out of the reciever.
Pics:
http://www.pyramydair.com/schematics/rwsmodel46e.asp
http://www.pyramydair.com/schematics/rws-48.html
The 3 screws and 3 pins:
http://i158.photobucket.com/albums/t99/rbva/pins.jpg
All the parts removed
http://i158.photobucket.com/albums/t99/rbva/simple.jpg